A semiconductor body often comprises a field-effect transistor. The field-effect transistor comprises a drain region, a source region and a channel region between the drain region and the source region. For a realization of a high voltage field-effect transistor, the field-effect transistor further comprises a drift region between the drain region and the channel region. A large distance between the source region and the drain region as well as a low doping concentration of the drift region are commonly used. This results in a high breakdown voltage between the source region and the drain region but also in a large on-resistance. For the realization of the chosen doping level inside the drift region, an additional ion implantation step and a further implantation mask are commonly used which may not be comprised by a standard complementary-metal-oxide-semiconductor integration technology process.
Document WO 2004/102670 A2 refers to semiconductor devices such as diodes and transistors with a field-shaping region having an insulating material.
In the document “Dielectric Resurf: Breakdown Voltage Control by STI Layout in Standard CMOS”, J. Sonsky, A. Hering a, International Electron Device Meeting IEDM, 5-7 Dec. 2005, IEDM technical digest, a field-effect transistor is described with an extended drain region comprising oxide-filled trenches.